Electric arc furnaces commonly include a furnace body consisting of a metalic shell and a refractery lining which define a hollow enclosure along with a removable cover through which one or more electrodes extend. Such furnace bodies are normally mounted on the platform which pivots about a horizontal axis for pouring molten metal from the furnace upon pivotal movement in one direction and for deslagging upon pivotal movement in an opposite direction. The furnace cover and electrodes are generally supported for translation from a position above the furnace to a remote position so that the furnace may be charged with a ferrous material such as pelletized iron or scrap. In order to permit such movement of the cover from above the furnace body to a remote position and for return movement thereof, the furnace electrodes must be elevated so that their lower ends do not contact the furnace body. Also, during the commencement of the furnace's operation the electrodes must be elevated above the charge of metallic material. The electrodes are then slowly fed into the furnace as a charge melts and the lower ends of the electrodes become worn or broken away. For these reasons, electrodes are normally mounted on a support assembly which is constructed and arranged for controlled vertical movement.
One type of electrode support assembly includes an electrode arm which carries a clamp at one end for engaging the electrode and the other end of which is supported by means of an elongated column member. The column in turn is supported for vertical movement. One advantageous means for vertically moving such columns includes a cable and sheave assembly. The cable may, for example, be wrapped around a drum and extend from there around one or more sheaves mounted on the column and with the opposite end of the cable dead-ended to the support structure. In this type of apparatus there is an inherent danger that in the event of a failure of the supporting structure, the electrode and its support structure will fall rapidly onto the furnace causing considerable damage.